光子晶体太赫兹波导带隙的研究

Study on Band Gap Structures of Photonic Crystal Fiber as Terahertz Waveguide

提出了一种光子晶体太赫兹波导,该波导包层为硅介质中含有按三角形格子周期排列的空气孔,纤芯为有机材料聚乙烯。这种波导是一种带隙效应波导。首先介绍平面波法(PWM)的理论,然后应用平面波法分析了这种光子晶体太赫兹波导的带隙结构,研究空气填充率变化对光子带隙结构的影响,得到了光子晶体太赫兹波导周期性结构的结构参数及与其相对应的导波频率。分析结果表明,增大空气填充率,可得到多条带隙和较大的带隙宽度,更易于实现纤芯导光。保持空气填充率不变,仅改变空气空间距可以在保持带隙结构不变条件下改变光子晶体太赫兹波导的导光频率。

A new type of photonic crystal fiber as terahertz（THz） waveguide has been designed. The cladding layer of this waveguide is triangular lattice with circular air holes in silicon, while the core is polythene. At first, the bandgap distribution characteristic of this photonic crystal terahertz waveguide and how the air-filling factors affect the band gap distribution characteristic have been investigated by using plane wave method（PWM）. The structural parameters of this photonic crystal terahertz waveguide with circular structure and the frequency guided in the waveguide have been obtained. Results show that the more band gaps and the broader band gaps can be obtained while the air-filling factors increase. Changing the space between air holes and holding the same air-filling factors can change the frequency guided in the waveguide.